In Europe, Onsen have already been used for the purposes of medical treatment. In Japan however, since ancient times, there is a custom known as "Toji" in Japanese, which involves people bathing in onsen situated in the middle of natural environments to help them recover after an illness, or maintain their health and wellbeing. This is what onsen are all about - giving yourself up to nature and the slow passing of time in order to draw out the natural healing power that our bodies essentially possess. Japan, a chain of volcanic islands, is a treasure chest of these kinds of hot springs.
It is blessed with some of the most eminent natural locations in the world, which have resulted in hot springs that continue to be used as a natural way to revitalise and relax the body and mind.
There are onsen nestled deep within beautiful and unspoilt areas of Japan, and with such a precious and historical onsen culture still alive throughout the whole country, why not visit one of these 'hidden spas' to experience a distinctive and fascinating slice of 'real' Japan, and find out just how enjoyable and relaxing they are.
In Japan, a law was created known as the 'onsenhou' (Hot Spring Law). Based on this law, a natural spring that contains over a defined amount of natural chemical components, and is over a temperature of 25 degrees at its point of release, is officially considered an 'onsen'.
There are a number of different onsen categories, according to chemical composition and temperature.
We, the HITOU - Japan Association of Secluded Hot Spring Inns continue to study about the best ways to ensure onsen are well managed and moderated, and that our earth's resources are carefully protected and preserved, while endeavouring to make more information available about the various classifications and categories of onsen (sources with a continuous flow, or onsen that are circulated etc.)
1. Continuous flow from source (Gensen kakenagashi)
Whilst heat might be added, there is no water added to this type of bath. With this kind of system, the high temperatures at the source are made more moderate and suitable for bathing by the use of heat-exchange devices either at the point where the water enters the bath, or in the bath itself.
The hot spring of a 'Gensen kakenageshi' bath is always released without being used in a circulation system.
2. Continuous flow (Kakenagashi)
In order to maintain the moderate temperature of this type of bath, both water and heat are added to the water supply. Like the 'Gensen' varient of 'Kakenagashi' - once the water enters the bath, it is released and does not go through a circulation system.
3. Direct flow from source - heated and circulation bath system
The hot spring supply is untouched as it enters the bath from the entry point, but in order to keep the water at a suitable temperature, a circulation system is used.
4. Direct flow from source - heated, filtered, sterilised, and circulation system.
The hot spring supply is untreated as it enters the bath from the entry point, but in order to keep the water at a suitable temperature, a circulation system is used to heat the water, whilst also purifying and sterilising it.
5. Hot spring supply is heated, filtered and sterilised before entering the bath.
As soon as the hot spring is supplied to the bath, in order to keep the water at a consistent volume and temperature, the water is first circulated, during which time it is also purified and sterilised before once more being released into the bath to be used.